Country legend Merle Haggard sat down with Men's Journal recently for a unique, personal interview, and the star didn't hold back. Haggard took the opportunity to share his feelings on a wide range of topics, from marijuana use to prison to his friend Johnny Cash.

Haggard used to be on the anti-marijuana side of the fence, but has since changed his tune, as evidenced by a track on his latest record with Willie Nelson titled "It's All Going to Pot.” He says the shift in perspective is due to a combination of education on the matter and maturing as an adult.

"At the time I wrote 'Okie From Muskogee,' I didn't smoke," he explains. "It was 68. I thought it was responsible for the flower children walking around with their mouths open. It was not so. But if a guy doesn't learn anything in 50 years, theres something wrong with him."

When asked about a song he wrote for the new album called "Missing Ol Johnny Cash," the icon also shared his feelings about the fellow legend and their close relationship.

"Johnny Cash was a special friend to me. We understood each other – we had the same upbringing, the same sense of humor," he recalls.

Haggard says Cash even thought it was Haggard who was the real deal, not him.

The artist told Cash it was just that he'd spent some time in prison, but otherwise they weren't all that different. Prison, Haggard explains, can teach you about honesty and integrity.

"In that environment, if you tell someone you're gonna do something on a Tuesday, you better do it, because you can't get away from them," he muses. But his opinion on prison isn't all about its character development.

"Prison is the biggest business in America," he says. "[If] you got the money, you can build a prison out in Nevada and it'll be filled before you finish building it. That's a fact, and that's a shame.”

Haggard and Nelsons new duet record, Django and Jimmie, released in June, debuted at No. 1 on the Billboard Country Albums Chart and No. 7 on the Billboard Top 200 Albums Chart.